Christian Borntraeger
2020-Jun-26 05:24 UTC
[Bridge] linux-next: umh: fix processed error when UMH_WAIT_PROC is used seems to break linux bridge on s390x (bisected)
On 26.06.20 04:54, Luis Chamberlain wrote:> On Wed, Jun 24, 2020 at 08:37:55PM +0200, Christian Borntraeger wrote: >> >> >> On 24.06.20 20:32, Christian Borntraeger wrote: >> [...]> >>> So the translations look correct. But your change is actually a sematic change >>> if(ret) will only trigger if there is an error >>> if (KWIFEXITED(ret)) will always trigger when the process ends. So we will always overwrite -ECHILD >>> and we did not do it before. >>> >> >> So the right fix is >> >> diff --git a/kernel/umh.c b/kernel/umh.c >> index f81e8698e36e..a3a3196e84d1 100644 >> --- a/kernel/umh.c >> +++ b/kernel/umh.c >> @@ -154,7 +154,7 @@ static void call_usermodehelper_exec_sync(struct subprocess_info *sub_info) >> * the real error code is already in sub_info->retval or >> * sub_info->retval is 0 anyway, so don't mess with it then. >> */ >> - if (KWIFEXITED(ret)) >> + if (KWEXITSTATUS(ret)) >> sub_info->retval = KWEXITSTATUS(ret); >> } >> >> I think. > > Nope, the right form is to check for WIFEXITED() before using WEXITSTATUS().But this IS a change over the previous code, no? I will test next week as I am travelling right now.
Christoph Hellwig
2020-Jun-26 09:00 UTC
[Bridge] linux-next: umh: fix processed error when UMH_WAIT_PROC is used seems to break linux bridge on s390x (bisected)
On Fri, Jun 26, 2020 at 07:22:34AM +0200, Christian Borntraeger wrote:> > > On 26.06.20 04:54, Luis Chamberlain wrote: > > On Wed, Jun 24, 2020 at 08:37:55PM +0200, Christian Borntraeger wrote: > >> > >> > >> On 24.06.20 20:32, Christian Borntraeger wrote: > >> [...]> > >>> So the translations look correct. But your change is actually a sematic change > >>> if(ret) will only trigger if there is an error > >>> if (KWIFEXITED(ret)) will always trigger when the process ends. So we will always overwrite -ECHILD > >>> and we did not do it before. > >>> > >> > >> So the right fix is > >> > >> diff --git a/kernel/umh.c b/kernel/umh.c > >> index f81e8698e36e..a3a3196e84d1 100644 > >> --- a/kernel/umh.c > >> +++ b/kernel/umh.c > >> @@ -154,7 +154,7 @@ static void call_usermodehelper_exec_sync(struct subprocess_info *sub_info) > >> * the real error code is already in sub_info->retval or > >> * sub_info->retval is 0 anyway, so don't mess with it then. > >> */ > >> - if (KWIFEXITED(ret)) > >> + if (KWEXITSTATUS(ret)) > >> sub_info->retval = KWEXITSTATUS(ret); > >> } > >> > >> I think. > > > > Nope, the right form is to check for WIFEXITED() before using WEXITSTATUS(). > > But this IS a change over the previous code, no? > I will test next week as I am travelling right now.I'm all for reverting back to the previous behavior. If someone wants a behavior change it should be a separate patch. And out of pure self interest I'd like to see that change after my addition of the kernel_wait helper to replace the kernel_wait4 abuse :)